This short (4 min) video shows aspects of the Harlows’ experiments with baby rhesus monkeys, who preferred to spend time with their contact-comforting cloth-covered mother rather than the wire mother who provided them with food.
This video does a good job in highlighting some of the ethical concerns we would now have with this kind of experiment – the emotional harm suffered by the monkeys. Textbooks usually counter the unethical aspects with the importance of the study in changing ideas about attachment. The Harlows’ study was influential on Bowlby’s theory of attachment, for example: Bowlby’s concept of the ‘safe base’ being linked to the comfort and security that the young rhesus monkeys were searching for.